Area Monitoring for Detection of Leaks and/or Flames

ABSTRACT

A solution for monitoring an area for the presence of a flame and/or a leak, such as from a pressurized fluid, is provided. An imaging device can be used that acquires image data based on electromagnetic radiation having wavelengths only corresponding to at least one region of the electromagnetic spectrum in which electromagnetic radiation from an ambient light source is less than the electromagnetic radiation emitted by at least one type of flame for which the presence within the area is being monitored. An acoustic device can be used that is configured to acquire acoustic data for the area and enhance acoustic signals in a range of frequencies corresponding to a leak of a pressurized fluid present in the area.

REFERENCE TO PRIOR APPLICATIONS

The current application claims the benefit of co-pending U.S.Provisional Application No. 61/213,877, titled “Method and device fordetection of leaks and or flames in a monitored area,” which was filedon 23 Jul. 2009, and which is hereby incorporated by reference.

GOVERNMENT LICENSE RIGHTS

The U.S. Government has a paid-up license in this invention and theright in limited circumstances to require the patent owner to licenseothers on reasonable terms as provided for by the terms of Contract No.NNX09CB42C awarded by National Aeronautics and Space Administration(NASA).

TECHNICAL FIELD

The disclosure relates generally to monitoring areas, and moreparticularly, to monitoring areas that can include fluids, particularlyflammable, pressurized fluids.

BACKGROUND ART

Hydrogen gas is colorless and odorless. Hydrogen burns in air with aninvisible flame in an outdoor setting under normal daylight conditions.Due to the small size of the hydrogen molecule, it is extremelydifficult to render mechanical joints leak free without welding. Somejoints, such as those found at facilities where hydrogen is loaded andstored, must have removable joints for connection, e.g., to deliveryvehicles. Similarly, at end-use sites, such as a launch vehicle,removable connections must exist to enable filling of onboard tanks.Hydrogen gas is commonly detected using fixed gas detectors. Outdoors,hydrogen is rapidly dispersed by moving air due to its low molecularweight and density. Further, hydrogen has a low ignition energy and alow threshold concentration, making hydrogen fires a significant hazardin such areas. The problem is further compounded for operations, such aslaunch complexes, where large quantities of hydrogen and oxidizer inclose proximity dictates safety regulations that preclude the use oftypical handheld leak or flame detectors by operators to confirm leaksor flames sensed by fixed instruments. Use of fixed leak detectioninstruments can be problematic due to the ease with which hydrogendisperses outdoors due to air currents. Depending on the location of theleak and the detector(s), the leak may need to be large in order toregister on the detector.

For many applications, non-imaging flame detectors do not providedesirable features, such as flame size identification and localization,within a monitored area. Various approaches seek to detect flames and/orleaks using single spectrum, multi-spectrum, non-imaging and imagingdevices. Such devices can utilize ultraviolet (UV), near infrared (NIR),or infrared (IR) detection approaches to image electromagnetic emissioncharacteristics of flames in general or flames resulting from theburning of specific materials, such as carbon compounds in air. To date,while many current devices can effectively identify a flame in amonitored area, these devices are susceptible to false indications offlames, e.g., due to reflections of flames, sunlight (direct orreflected), and reflections from vegetation. As a result, operationspersonnel can be required to review imagery to formulate a correctresponse to the device identifying a fire in a monitored area.Additionally, such devices are not suitable for use in mission criticalapplications, such as rocket launch operations, due to the costassociated with mission aborts resulting from false alarms.

In an illustrative prior art flame detection approach, a multispectralmethod of flame detection employs three infrared detectors andassociated filters to select portions of the infrared spectrum. A useruses the device of this approach in the manner of a binocular to viewimagery based on spectral content in the near infrared (NIR) region ofthe spectrum below 800 nanometers (nm) or 1100 nm. The filters renderinvisible flames visible due to water emissions in the 850-1250 nmportion of the electromagnetic spectrum. The device can trigger an alarmfor the user when a flame is detected.

In another illustrative prior art flame detection approach, an imagingflame detection system employs a camera with an 1140 nm band pass filterto select emissions from flames. The system performs size and flickeranalysis on blobs extracted from the imagery using a stored reference offlame and false alarm signatures to discriminate between a flame or afalse alarm.

In still another illustrative prior art flame detection approach, anon-imaging approach to flame detection utilizes two infrared sensorsand one ultraviolet sensor. Cross correlation between the infrared andultraviolet signals is performed to discriminate between a flame and areflection of a flame.

The sound made by a pressurized gas or liquid escaping from an orificeis determined by the source pressure and the size of the orifice, whichserve to generate turbulence in the air in the immediate vicinity of theleak or flame. Additionally, the resulting turbulence is also dependenton the particular material of the leak or flame. The turbulence, whichresults in rapid pressure fluctuations in the air near the leak or flamesource can be detected with appropriate acoustic pressure transducers.Pressure fluctuations due to a leak or flame typically have a broadspectral content with maximum intensity in the ultrasonic portion of thespectrum (e.g., 20-50 kHz). Ultrasonic energy experiences significantatmospheric attenuation as it emanates from a source, e.g., typicallyapproximately twenty-five decibels per one hundred feet at twentykilohertz. The attenuation increases with the second power of distancedue to circular spreading and with the second power of frequency due toatmospheric absorption.

Devices to detect ultrasonic waves have been proposed for leak detectionat distances up to twenty-five feet in a normal outdoor acousticenvironment. In an illustrative prior art leak detection approach, anomni-directional microphone detects ultrasonic signals, which areprocessed using amplitude and temporal duration thresholds to identifyleaks from background noise.

Reflecting concave surfaces, such as spherical or paraboloid sections,can focus energy incident on the surface to a single point, referred toas the focal point. Such surfaces are often used as radar and satellitedish antennas to focus electromagnetic waves and for surveillance andtracking certain animals using acoustic waves. Some approaches to leakdetection have proposed the use of parabolic antennas to assist inlocalization of the leak source.

SUMMARY OF THE INVENTION

Aspects of the invention provide a solution for monitoring an area forthe presence of a flame and/or a leak, such as from a pressurized fluid.An imaging device can be used that acquires image data based onelectromagnetic radiation having wavelengths only corresponding to atleast one region of the electromagnetic spectrum in whichelectromagnetic radiation from an ambient light source is less than theelectromagnetic radiation emitted by at least one type of flame forwhich the presence within the area is being monitored. An acousticdevice can be used that is configured to acquire acoustic data for thearea and enhance acoustic signals in a range of frequenciescorresponding to a leak of a pressurized fluid present in the area.

A first aspect of the invention provides a system comprising: at leastone sensing component, the at least one sensing component including: animaging device, wherein the imaging device is configured to acquireimage data for an area based on electromagnetic radiation havingwavelengths only corresponding to at least one region of theelectromagnetic spectrum in which electromagnetic radiation from anambient light source is less than the electromagnetic radiation emittedby at least one type of flame; and an acoustic device, wherein theacoustic device is configured to acquire acoustic data for the area; acomputer system including at least one computing device, wherein thecomputer system is configured to monitor the area by performing a methodcomprising: evaluating the image data for a presence of a flame of theat least one type of flame; evaluating the acoustic data for a presenceof at least one of: the flame or a leak of a pressurized fluid; andproviding monitoring data for use by a user based on the evaluatedpresence of at least one of: the flame or the leak.

A second aspect of the invention provides a system comprising: at leastone sensing component, the at least one sensing component including: animaging device, wherein the imaging device is configured to acquireimage data for an area; and an acoustic device, wherein the acousticdevice is configured to acquire acoustic data for the area and enhanceacoustic signals in a range of frequencies corresponding to a leak of apressurized fluid present in the area, the acoustic device including: areflective surface, wherein the reflective surface is at least one of: aparabolic or a spherical shape having a focal length that is at least aslarge as an aperture of the reflective surface; and a transducerconfigured to convert acoustic signals acquired at a focal point of thereflective surface into acoustic data; a computer system including atleast one computing device, wherein the computer system is configured tomonitor the area by performing a method comprising: evaluating the imagedata for a presence of a flame of the at least one type of flame;evaluating the acoustic data for a presence of at least one of: theflame or a leak of the pressurized fluid; and providing monitoring datafor use by a user based on the evaluated presence of at least one of:the flame or the leak.

A third aspect of the invention provides a system comprising: an imagingdevice, wherein the imaging device is configured to acquire image datafor an area based on electromagnetic radiation having wavelengths onlycorresponding to at least one region of the electromagnetic spectrum inwhich electromagnetic radiation from an ambient light source is lessthan the electromagnetic radiation emitted by at least one type offlame; and a computer system including at least one computing device,wherein the computer system is configured to monitor the area byperforming a method comprising: evaluating the image data for a presenceof a flame of the at least one type of flame; and providing monitoringdata for use by a user based on the evaluated presence of the flame,wherein the monitoring data includes annotated image data of the area.

Other aspects of the invention provide methods, systems, programproducts, and methods of using and generating each, which include and/orimplement some or all of the actions described herein. The illustrativeaspects of the invention are designed to solve one or more of theproblems herein described and/or one or more other problems notdiscussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings that depict various aspects of the invention.

FIG. 1 shows an illustrative environment for monitoring an areaaccording to an embodiment.

FIG. 2 shows an illustrative implementation of the environment of FIG. 1according to an embodiment.

FIG. 3 shows emission lines observed when hydrogen burns in air forillustrative portions of the electromagnetic spectrum.

FIG. 4 shows typical solar radiation at the surface of the earth for anillustrative portion of the electromagnetic spectrum.

FIG. 5 shows an illustrative image of an outdoor hydrogen flame.

FIG. 6 shows an illustrative image of the outdoor hydrogen flameacquired by a sensing device according to an embodiment.

FIG. 7 shows an illustrative process for automatically identifying aflame present in a monitored area using image data according to anembodiment.

FIGS. 8A and 8B show illustrative two-dimensional slices of a sphericalsurface and a parabolic surface, respectively.

FIG. 9 shows an illustrative acoustic sensing device according to anembodiment.

FIGS. 10A-10C show illustrative acoustic frequency spectra according toan embodiment.

FIG. 11 shows an illustrative process for automatically identifying thepresence of a leak and/or a flame in a monitored area using acousticdata according to an embodiment.

It is noted that the drawings may not be to scale. The drawings areintended to depict only typical aspects of the invention, and thereforeshould not be considered as limiting the scope of the invention. In thedrawings, like numbering represents like elements between the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, aspects of the invention provide a solution formonitoring an area for the presence of a flame and/or a leak, such asfrom a pressurized fluid. An imaging device can be used that acquiresimage data based on electromagnetic radiation having wavelengths onlycorresponding to at least one region of the electromagnetic spectrum inwhich electromagnetic radiation from an ambient light source is lessthan the electromagnetic radiation emitted by at least one type of flamefor which the presence within the area is being monitored. An acousticdevice can be used that is configured to acquire acoustic data for thearea and enhance acoustic signals in a range of frequenciescorresponding to a leak of a pressurized fluid present in the area. Asused herein, unless otherwise noted, the term “set” means one or more(i.e., at least one) and the phrase “any solution” means any now knownor later developed solution.

Embodiments of the invention can address one or more problems ofprevious approaches to flame and/or leak detection. For example, anembodiment provides an automated approach to flame and/or leakdetection, which can be integrated with other external systems and/orprovide flame information, such as flame size, localization, and/or thelike for use by another system and/or a user. An embodiment provides aflame detection solution, which can ignore reflections, e.g., ofacceptable flames (e.g., at a flare stack, welding site, and/or thelike), sunlight, and/or the like. Another embodiment provides a flamedetection solution, which can detect various types of flames, includingflames produced by high pressure fluid (e.g., gas or liquid) emanatingfrom a small orifice, hydrogen flames, which can exhibit substantiallyno periodic variability, and/or the like. Furthermore, an embodimentprovides a leak detection solution, which can discriminate loudcontinuous ultrasound background from a leak, as well as detectrelatively small leaks for various applications.

Additional aspects of the invention are shown and described herein withreference to the automated detection of a hydrogen leak and/or flamewithin a monitored area. However, it is understood that aspects of theinvention apply to other types of burning and/or leaking fluids,particularly where such a leak and/or flame is the result of materialpassing through an orifice or other opening under some pressure higherthan the atmospheric pressure. Embodiments of the invention can enablepositioning of sensing devices for detecting a leak and/or flame at afurther distance from a potential leak/flame source than prior artapproaches. The distance can enable monitoring to be performed in asafer manner and/or with fewer sensing devices.

Turning to the drawings, FIG. 1 shows an illustrative environment 10 formonitoring an area according to an embodiment. To this extent,environment 10 includes a computer system 20 that can perform a processdescribed herein in order to monitor an area to automatically detectleaks and/or flames. For example, computer system 20 is shown includinga monitoring program 30, which makes computer system 20 operable tomonitor the area by performing a process described herein.

Computer system 20 is shown including a processing component 22 (e.g.,one or more processors), a storage component 24 (e.g., a storagehierarchy), an input/output (I/O) component 26 (e.g., one or more I/Ointerfaces and/or devices), and a communications pathway 28. In general,processing component 22 executes program code, such as monitoringprogram 30, which is at least partially fixed in storage component 24.While executing program code, processing component 22 can process data,which can result in reading and/or writing transformed data from/tostorage component 24 and/or I/O component 26 for further processing.Pathway 28 provides a communications link between each of the componentsin computer system 20. I/O component 26 can comprise one or more humanI/O devices, which enable a human user 12 to interact with computersystem 20 and/or one or more communications devices to enable one ormore external devices, such as a sensing component 14 and/or a systemuser 12, to communicate with computer system 20 using any type ofcommunications link. To this extent, computer system 20 can manage a setof interfaces (e.g., graphical user interface(s), application programinterface, and/or the like) that enable human and/or system users 12,sensing component 14, and/or the like, to interact with computer system20. Furthermore, monitoring program 30 can manage (e.g., store,retrieve, create, manipulate, organize, present, etc.) the data, such asmonitoring data 34, using any solution.

In any event, computer system 20 can comprise one or more of anycombination of various types of computing devices. For example, computersystem 20 can comprise one or more general purpose computing articles ofmanufacture (e.g., computing devices) capable of executing program code,such as monitoring program 30, installed thereon. As used herein, it isunderstood that “program code” means any collection of instructions, inany language, code or notation, that cause a computing device having aninformation processing capability to perform a particular action eitherdirectly or after any combination of the following: (a) conversion toanother language, code or notation; (b) reproduction in a differentmaterial form; and/or (c) decompression. To this extent, monitoringprogram 30 can be embodied as any combination of system software and/orapplication software.

Furthermore, monitoring program 30 can be implemented using a set ofmodules 32. In this case, a module 32 can enable computer system 20 toperform a set of tasks used by monitoring program 30, and can beseparately developed and/or implemented apart from other portions ofmonitoring program 30. As used herein, the term “component” means anyconfiguration of hardware, with or without software, which implementsthe functionality described in conjunction therewith using any solution,while the term “module” means program code that enables a computersystem 20 to implement the actions described in conjunction therewithusing any solution. When fixed in a storage component 24 of a computersystem 20 that includes a processing component 22, a module is asubstantial portion of a component that implements the actions.Regardless, it is understood that two or more components, modules,and/or systems may share some/all of their respective hardware and/orsoftware. Furthermore, it is understood that some of the functionalitydiscussed herein may not be implemented or additional functionality maybe included as part of computer system 20.

When computer system 20 includes multiple computing devices, thecomputing devices can communicate over any type of communications link.Further, while performing a process described herein, computer system 20can communicate with one or more other computer systems and devices,such as user 12 and/or sensing component 14, using any type ofcommunications link. In either case, the communications link cancomprise any combination of various types of wired and/or wirelesslinks; comprise any combination of one or more types of networks; and/orutilize any combination of various types of transmission techniques andprotocols.

Additionally, each computing device can implement only a portion of theactions described herein with respect to computer system 20. To thisextent, each computing device can have only a portion of monitoringprogram 30 fixed thereon (e.g., one or more modules 32). However, it isunderstood that computer system 20 and monitoring program 30 are onlyrepresentative of various possible equivalent computer systems that mayperform a process described herein. To this extent, in otherembodiments, the actions implemented by computer system 20 can be atleast partially implemented by one or more computing devices thatinclude any combination of general and/or specific purpose hardware withor without program code. In each embodiment, the hardware and programcode, if included, can be created using standard engineering andprogramming techniques, respectively.

FIG. 2 shows an illustrative implementation of environment 10 accordingto an embodiment. In this case, computer system 20 is implemented usinga pair of computing devices 16A, 16B, and sensing component 14 includestwo sensing devices 18A, 18B. It is understood that sensing component 14and computer system 20 can include any number of devices. Additionally,it is understood that environment 10 can include any number of computersystems 20 and sensing components 14. In general, the sensing devices18A, 18B capture raw monitoring data 34 (FIG. 1) for an area beingmonitored, which is provided to computer system 20 for furtherprocessing. In an embodiment, computing device 16B comprises a signalprocessing computing device 16B, which performs various preliminaryprocessing actions on the raw monitoring data 34 received from sensingcomponent 14 to generate intermediary monitoring data 34B, whilecomputing device 16A comprises a main processing computing device 16A,which performs higher level processing and analysis of the raw and/orintermediary monitoring data 34B to generate high level monitoring data34A. Computing device 16A can provide some or all of the monitoring data34 for use by one or more users 12. For example, computing device 16Acan provide raw and/or annotated video data, raw and/or edited audiodata, alarm data, notification data, action data, and/or the like, foruse by one or more users 12.

In FIG. 2, sensing device 18A comprises an imaging device, such as anear infrared imaging device, and sensing device 18B comprises anacoustic sensor, such as an ultrasonic sensing device. Each sensingdevice 18A, 18B is shown operatively coupled to the signal processingcomputing device 16B. Computing device 16B can comprise a processingcomponent 22B to control operation of the computing device 16B and/orthe various sensing devices 18A, 18B. For example, processing component22B can comprise a digital signal processor, an embedded processor,fixed logic (such as a field programmable gate array (FPGA)), and/or thelike. In any event, image data, such as near infrared image data, can beprovided from sensing device 18A to an I/O interface 26B1 of computingdevice 16B, such as a frame grabber, which can convert the image data(e.g., video) into digital data and store the digital data as monitoringdata 34B in a memory 24B of computing device 16B. Similarly, acousticdata, such as analog ultrasonic data, can be provided from sensingdevice 18B to another I/O interface 26B2 of computing device 16B, suchas an analog to digital converter, which can convert the acoustic datainto digital data and store the digital data as monitoring data 34B inthe memory 24B.

The main processing computing device 16A can access the monitoring data34B stored in the memory 24B of computing device 16B using any type ofconnection. To this extent, computing device 16A can include aprocessing component 22A (e.g., a general purpose processor executingmonitoring program cede 30), which performs operations on monitoringdata 34A stored in memory 24A and/or monitoring data 34B stored inmemory 24B. Processing component 22A can further control various I/Ointerfaces 26A1-4. For example, I/O interface 26A1 can enable one ormore human interface devices (e.g., display, keyboard, mouse, and/or thelike), to interact with computing device 16A.

Furthermore, I/O interfaces 26A2-4 can provide various types ofmonitoring data 34A, 34B as output data, such as alarm indications whena leak or flame is detected by computing device 16A, for use by one ormore users 12. For example, I/O interface 26A2 can comprise a discreteoutput device for providing a set of alarm (or non-alarm) outputs, e.g.,to a warning light, a buzzer, a horn, and/or the like. I/O interface26A3 can comprise an acoustic output device, e.g., which generates aheterodyned version of the acoustic input data that is within the rangeof human hearing. A human user 12 can use the output provided by I/Ointerface 26A3 to, for example, listen to a frequency shifted version ofthe acoustic input signal captured by sensing device 18B. I/O interface26A4 can comprise circuitry configured to generate a video output, whichcan comprise an annotated version of the image data acquired by sensingdevice 18A. An illustrative annotation comprises pseudo-coloring ofareas with flames. Other coloring can be added to highlight area(s) inthe image data containing motion that may be a possible flame but couldnot be classified as such by the flame detection algorithms. Still otherannotations can include labeling (e.g., by symbol, text, and/or thelike) various areas of interest, and other methods of annotating as maybe appropriate to the presentation of the image.

As discussed herein, sensing component 14 can comprise one or moresensing devices 18A for acquiring image data of an area being monitoredby environment 10. In an embodiment, the image data is processed bycomputer system 20 to automatically monitor the area for a presence ofan undesirable flame, such as a hydrogen flame. In general, a flammablematerial burning in air produces an emission spectrum resulting from theexcitation of chemical bonds in the combustion products. For hydrogenburning in air, the primary product is water. During the burning ofhydrogen, molecular fragments, such as the OH⁻ radical, also may bepresent.

In an embodiment, sensing component 14 includes one or more sensingdevices 18A for acquiring image data corresponding to one or moreportions of the electromagnetic spectrum, which correspond towavelengths of radiation that are emitted by the undesirable flame. Thesensing device(s) 18A can comprise an imaging device that includes acamera, optics, filters and/or the like, which preferentially passradiation having the wavelengths of interest and/or block radiationhaving undesired wavelengths (e.g., unrelated to the flame of interest).The sensitivity of the sensing device 18A can be adjusted to recognizethe flame of one material while having reduced sensitivity to otherflames by proper selection of filters in the camera to be preferentiallysensitive to the emission spectrum of a desired burning material.

FIG. 3 shows emission lines observed when hydrogen burns in air forillustrative portions of the electromagnetic spectrum. The leftmostportion of the graph shows the ultraviolet through visible portion ofthe spectrum from 300 nanometers (nm) to 575 nm. Emission peaks are seenin the range from 300-325 nm, which are due to the OH⁻ radical. Theright portion of the graph depicts emissions in the near infraredportion of the electromagnetic spectrum from 800-1250 nm. In this band,various stretching, bending, and rotational modes of a water moleculeresult in nearly continuous emissions from 800 nm to 1250 nm. While notshown FIG. 3, burning hydrogen also comprises emission lines centeredaround 1380 and 1900 nm. To monitor an area for the presence of anunwanted hydrogen flame, sensing component 14 can include sensingdevice(s) 18A that acquire image data primarily corresponding towavelengths of radiation in one or more of: 300-325 nm, 800-1250 nm,1300-1400 nm, and/or 1800-1950 nm.

Additional sources of electromagnetic radiation (e.g., ambient lightsources) can make successful evaluation of image data for the presenceof a flame more difficult for portions of the electromagnetic spectrumin which the flame and the other source(s) both emit electromagneticradiation of the corresponding wavelengths. In particular, if theradiation of another source of electromagnetic radiation in a monitoredarea at a relevant wavelength is sufficiently bright, specular anddiffuse reflections of objects in the monitored area may be strongerthan the radiation from a flame in the same area. For example, inoutdoor applications, the radiation of the sun can reduce theeffectiveness of evaluating image data for the presence of a hydrogenflame for certain portions of the electromagnetic spectrum.

In an embodiment, sensing device(s) 18A acquire image data primarilycorresponding to wavelengths of radiation in which radiation from eachambient light source is sufficiently low and/or substantiallynon-existent. In an embodiment, a range of wavelengths is selected inwhich the spectral irradiance of the ambient light source(s) is lessthan the emission of a flame for the same range of wavelengths. Forexample, the range of wavelengths can be selected such that a flame willemit at least twice the amount of spectral irradiance that may bepresent due to an ambient light source.

For an outdoor application, an ambient light source can comprise thesun. FIG. 4 shows typical solar radiation at the surface of the earthfor an illustrative portion of the electromagnetic spectrum. At the topof the earth's atmosphere, solar radiation is well approximated by blackbody radiation at a temperature of 5250° K. Due to absorption thatoccurs due to molecules present in the atmosphere, certain regions ofthe spectrum can have significantly reduced solar radiation when thesolar radiation reaches the earth's surface. For example, little or nosolar radiation is present at the earth's surface in several regions ofthe electromagnetic spectrum primarily due to the presence of ozone(O₃), oxygen molecules (O₂), water vapor (H₂O), and carbon dioxide (CO₂)in the atmosphere. While sunlight is shown and described herein asillustrative ambient light, it is understood that the spectralirradiance for other light sources, such as artificial light sources,can be similarly analyzed.

In an embodiment, sensing component 14 includes one or more sensingdevices 18A for acquiring image data for a monitored area correspondingto only one or more of the regions in which little or no radiation ispresent from an ambient light source, e.g., to evaluate the monitoredarea for the presence of a flame. For example, a flame that produceswater as a byproduct, such as hydrogen burning in air or oxygen,produces emission lines in the same spectral regions in which solarradiation is removed by water vapor in the atmosphere. In an applicationthat monitors an outdoor area for the presence of such a flame, sensingdevice(s) 18A can acquire image data corresponding to only one or moreof these regions of the electromagnetic spectrum. To this extent,sensing device(s) 18A can acquire image data corresponding to one ormore of regions 2A, 2B, and 2C of the electromagnetic spectrum, in whichthe solar radiation is typically completely removed at the earth'ssurface (e.g., sea level).

However, for some applications, current sensing device(s) 18A thatacquire image data corresponding to one or more of regions 2A, 2B, and2C are too expensive and/or provide insufficient resolution to imageflames at a desired distance. Currently, cameras constructed usingcharge coupled device (CCD) technology are relatively low cost andpossess higher sensitivity and resolution in regions 4A, 4B, and 4C toenable image acquisition and evaluation at larger distances. To thisextent, in an embodiment, sensing component 14 includes sensingdevice(s) 18A configured to acquire image data corresponding to one ormore of regions 4A, 4B, and 4C of the electromagnetic spectrum.

Reflections from vegetation and/or clouds can be particularly strong inregions 4A and 4B of the electromagnetic spectrum. To this extent, forapplications in which such reflections may be present in the monitoredarea, the sensing device(s) 18A can be configured to acquire image datacorresponding to region 4C. While region 4C is at the limits of theresponse of current CCD cameras, the reduced sensitivity to radiationreflected from vegetation, clouds, and other outdoor sources can beadvantageous in enabling computer system 20 (FIG. 1) to evaluate theimage data where such reflections may be present for the presence of anundesired flame.

Returning to FIG. 2, an embodiment of sensing device 18A can besensitive to the radiation emission of a hydrogen flame (e.g., as shownin FIG. 3) in an outdoor environment where radiation from sunlight(e.g., as shown in FIG. 4) may be present. In a more particularembodiment, sensing device 18A is configured to acquire image datacorresponding to region 4C. For example, sensing device 18A can includea camera 40A and a lens 40B that are sensitive to electromagneticradiation having wavelengths in the range of approximately 1100-1250 nm.To eliminate radiation in other spectral regions to which the camera 40Amay be sensitive, sensing device 18A can further include a low passfilter 40C, which is placed in front of the lens 40B. In an embodiment,the cut on wavelength of the filter 40C can comprise approximately 1150nm. Camera 40A can effectively provide a cut off wavelength ofapproximately 1250 nm, e.g., due to current limits of the CCDtechnology. In this case, sensing device 18A can act as a band passfilter for 1150-1250 nm radiation, which has a high transmissionefficiency of a low pass filter. It is understood that the range of1150-1250 nm is only illustrative, and other ranges of wavelengthscorresponding to region 4C can be implemented.

FIGS. 5 and 6 show illustrative images 34A, 34B, respectively, of anoutdoor hydrogen flame. In each image 34A, 34B, a hydrogen flame ispresent at location 42, which is emitted from a hydrogen feed tube 43.Image 34A was captured by a camera 40A and lens 40B without the presenceof a low pass filter 40C, while image 34B was captured by the sensingdevice 18A (FIG. 2) described above, including the low pass filter 40Cwith a cut on wavelength of approximately 1150 nm. As illustrated byimage 34A, the significant visible radiation present below 1150 nm, madethe relatively weak near infrared radiation of the flame undetectable inimage 34A. In contrast, by removing radiation having wavelengths belowapproximately 1150 nm, the infrared radiation emitted by the flame canbe readily detected in image 34B.

FIG. 7 shows an illustrative process for automatically identifying aflame present in a monitored area using image data according to anembodiment, which can be implemented by environment 10 (FIGS. 1 and 2).Referring to FIGS. 2 and 7, in action 102, computer system 20 receivesimage data 134A (e.g., as part of a video) acquired by sensing device18A and performs image processing on the image data 134A. In anembodiment, computer system 20 can receive and process image data atapproximately thirty frames per second. However, it is understood thatvarious imaging rates can be utilized. Regardless, computing device 16Bcan perform processing on each image in the video to enhance contrast,eliminate impulsive pixelated noise that might be erroneouslycategorized as motion, and/or the like, using standard processingapproaches, such as histogram stretching and equalization combined withlow pass and median filtering, and store the processed image data asmonitoring data 34B.

In action 104, computer system 20 can update a running backgroundcorresponding to the region being monitored based on the processed imagedata. For example, computing device 16B can obtain an initial backgroundimage, e.g., which is known not to include any moving objects orundesired flames, and store it as a running background as part ofmonitoring data 34B. Subsequently, computing device 16B can compare andupdate attributes of various pixels in a previously stored runningbackground with the attributes found in the processed image data. Forexample, relatively small changes to one or more attributes can bepropagated in the image data for the running background. In this case,the running background can be updated to reflect the current background,which may undergo gradual changes over time, e.g., due to the motion ofthe sun, clouds, fluctuations of leaves, and/or the like, therebyreducing any adverse effects that such gradual changes can have onevaluating the image data.

The running background can be used to isolate moving object(s) in thefield of view from the background. To this extent, in action 106,computer system 20 can segment the image data into zero or morecandidate objects. For example, computing device 16A can identifyregions of difference from the running background. In an embodiment,computing device 16A can use an adaptive thresholding technique toidentify the candidate object(s), if any. In an embodiment, one or moreregions within the image data that are known to contain acceptableflame(s), such as a flare stack, are excluded from the segmentingperformed by computer system 20. In action 108, computing device 16A canremove any candidate objects that are less than a minimum flame sizedetection limit, e.g., using standard morphological methods.

In action 110, computing device 16A can determine one or more objectproperties for each candidate object. The object properties can include,for example, a bounding box, a centroid, a major axis length, anorientation, a periphery, a solidarity, and/or the like, each of whichcan be determined using standard image processing methods. Computingdevice 16A also can calculate one or more additional properties of thegray scale region in the original image data corresponding to eachdetected candidate object, such as a root mean square (RMS) amplitude, aflicker frequency, and/or the like. In action 112, computing device 16Acan characterize one or more aspects of the motion of a candidateobject. For example, computing device 16A can calculate a trajectory ofthe center of mass for each candidate object that is a candidate flameand has been present for more than one sequential frame.

In action 114, computing device 16A can apply a set of flame detectionrules to all of the candidate objects. Such rules can include, forexample, variance of the center of mass, change in orientation or lengthof the major axis, flicker frequency and amplitude, irregularity of theedges, rapidity of changes to one or more aspects of the shape (e.g.,the periphery), and/or the like. Computing device 16A can identify anycandidate object that passes a sufficient number of the flame detectionrules (e.g., all of them) as a candidate flame. Additionally, computingdevice 16A can manage data identifying a duration for which eachcandidate object has been identified as a candidate flame. For example,computing device 16A can set a counter for each candidate object that isidentified as a candidate flame to record a number of consecutive framesthat the candidate object has been considered a candidate flame.

In action 116, for each candidate flame, computing device 16A candetermine whether the candidate flame has persisted for a minimum amountof time. For example, computing device 16A can determine if thecandidate flame has passed a sufficient amount of the flame detectionrules for a minimum number of consecutive frames (e.g., thirty frames).If not, computing device 16A also can determine if the candidate flamehas failed a certain number of the flame detection rules (e.g., one ormore) for a percentage of the time (e.g., five frames out of twenty). Ifso, in action 118, computing device 16A can reset the candidate flamedesignation corresponding to the candidate object.

In response to computing device 16A identifying a candidate flame thathas persisted for a sufficient amount of time, in action 120, computingdevice 16A can generate one or more types of monitoring data 1348indicating the presence of an undesired flame within the monitored area.For example, computing device 16A can prepare alarm annotated image(s)based on the image data 134A, which computing device 16A can provide forprocessing by/presentation to one or more users 12. The annotatedimage(s) can include an indication of the size, location, and/orcharacteristics of the detected flame(s). Similarly, computing device16A can generate and provide flame statistics, alarm messages, an alarm(e.g., discrete) signal, and/or the like, for use by one or more users12. The alarm signal can result in a displayed alarm (e.g., red light),an audible alarm (e.g., an alert sound), and/or the like, which canalert a user 12 of the detected flame.

As discussed herein, sensing component 14 can comprise one or moresensing devices 18B for acquiring acoustic data of an area beingmonitored by environment 10. In an embodiment, computer system 20processes the acoustic data to automatically detect a leak and/or flameof a pressurized fluid. In a more particular embodiment, one or moreacoustic sensing devices 18B are configured to be located fifty feet ormore from a potential leak source, while being capable of detecting verysmall leaks, e.g., less than 0.5 grams/second (g/sec) of a light gas,such as hydrogen. For example, an acoustic sensing device 18B cancomprise a high gain, directional antenna, which is optimized forperformance in the 10-50 kilohertz (kHz) frequency range. Such anacoustic sensing device 18B can detect leaks of less than 0.5 g/sec froma distance of approximately 50-75 feet in a normal outdoor acousticenvironment.

FIGS. 8A and 8B show illustrative two-dimensional slices of a sphericalsurface 44A and a parabolic surface 44B, respectively. The sphericalsurface 44A is defined by a center, C, and a radius of curvature, R. Thelocation of the focus point, FP, can be calculated using the formulaf=½*R, where f is the focal length. The parabolic surface 44B is definedby a diameter, D, and a sagittal depth, d. The focal length, f, whichcorresponds to the location of the focal point, FP, can be calculated asf=D²/16d.

For either surface 44A, 44B, when substantially parallel radiation 6 isincident on either shape, substantially all of the energy isconcentrated at the respective focal point, FP. To this extent, thesignal output of a transducer located at either focal point, FP, issubstantially higher for a source of radiation 6 when either surface44A, 44B is present versus when it is not present. In an ideal case, theincrease in signal level is proportional to the square of the apertureof the shape and the frequency of the incident radiation 6. For example,for the parabolic surface 44B, the maximum signal increase or gain, G,can be calculated by G=η(πDf/v)², where q is an efficiency factor, D isthe aperture, f is the frequency of the radiation 6, and v is thepropagation velocity of the radiation 6. The maximum gain is specifiedfor radiation received from a source on the main axis of the reflectivesurface 44B. The efficiency factor q is critical in practicalapplications as it can have a large variation dependent upon the chosendesign parameters and the nature of the radiation to be measured.

Use of a reflective surface 44A or 44B also increases the directionalsensitivity to incident radiation 6, which can be used, for example, tolocalize a signal source. The directional sensitivity is defined by thebeamwidth, which is the solid angle that defines the points at which thegain is reduced to ½ of the on-axis gain. The beam width, B, for aparabolic antenna is given by B=kv/fD, where k is a proportionalityfactor, D is the aperture, f is the frequency of the radiation 6, and vis the propagation velocity of the radiation 6.

FIG. 9 shows an illustrative acoustic sensing device 18B according to anembodiment. Contrary to prior art approaches, acoustic sensing device18B is configured for high gain at a relatively large distance from apotential leak source. Acoustic sensing device 18B includes a reflectivesurface (antenna) 46A and a transducer 46B. As illustrated, reflectivesurface 46A reflects acoustic signals received from a narrowly focuseddirectional area toward a focal point, FP, thereby providing mechanicalamplification of any on-axis/nearly on-axis acoustic signals arriving atacoustic sensor 18B. The reflective surface 46A can comprise a parabolicor spherical shape, and be configured for use with ultrasonic radiation6. The transducer 46B is configured to convert acoustic signals intoelectrical energy. To this extent, transducer 46B can include amicrophone 46C and a preamplifier 46D. Microphone 46C can be locatedsuch that its sensing area (e.g., diaphragm) is located at focal pointFP. Microphone 46C can comprise any type of microphone including, butnot limited to, a condenser microphone, an electret microphone, amicro-electro mechanical systems (MEMS) microphone, and/or the like.Preamplifier 46D can increase the output voltage of microphone 46C to astronger, more usable level for further processing, e.g., by computersystem 20. It is understood that preamplifier 46D also can provide anappropriate amount of analog anti-alias filtering in an embodiment.

Acoustic sensor 18B can hold transducer 46B in place using any solution.For example, acoustic sensor 18B can include a plurality of struts, eachof which is attached to reflective antenna 46A and transducer 46B with acorresponding set of clamps. Acoustic sensor 18B can further include oneor more protective elements. For example, microphone 46C can be coveredby a protective screen. Further, transducer 46B can be enclosed within ahousing configured to protect transducer 46B during outdoor operation.Transducer 46B can be operationally connected to one or more additionalcomponents, such as computer system 20, using any solution, e.g., a setof wires connected to preamplifier 46D, or the like.

Acoustic sensor 18B can be configured to enhance acoustic signals in arange of relevant frequencies and/or enhance acoustic signals receivedfrom a directional area corresponding to a location of a potential leakand/of flame source. For example, acoustic sensor 18B can be configuredwith a shape and focal length such that an acceptance angle of themicrophone 46C is matched to the reflective surface 46A, therebyproviding much higher gain for the relevant acoustic signals for thesame physical sized antenna 46A. In some applications, the acousticsignals of an evaluated condition, such as a leak or a flame, can bemuch softer than ambient noises. In this case, acoustic sensor 18B canprovide sufficient gain for the relevant frequencies and isolation fromsounds emanating from other sources to enable accurate evaluation forthe presence of the evaluated condition.

For high gain at large distances the aperture D and the efficiency q forthe acoustic sensor 18B can be made as large as practical. For outdoorapplications, a practical limit to the aperture D results from windresistance considerations. In an illustrative embodiment, the reflectivesurface 46A is a spherical section of approximately twelve inches indiameter. To increase the efficiency factor q, several factors can beconsidered. For example, the transducer 46B and any correspondingsupport structure (e.g., struts), protective elements, and/oroperational elements (e.g., wiring) should present a small cross sectionin the direction of the incident radiation 6 when compared with thewavelength of the incident radiation 6. For a typical leak, thefrequency of maximum signal intensity is approximately twenty-five kHz,which corresponds to a wavelength of 0.53 inches. In an embodiment, thelargest cross section of all the components relating to transducer 46Bis approximately half of the wavelength, or approximately 0.25 inches.

A second factor influencing the efficiency factor η is cancellation dueto unequal path lengths of the radiation 6 reflected into the transducerby the antenna. In particular, when the path lengths differ by amultiple of ½ of the wavelength of the incident radiation 6,cancellation due to destructive interference will occur. Since theradiation 6 from a leak is broadband in nature, wavelength-dependentcancellation is undesirable as the shape of the frequency spectrum willbe modified. In an embodiment, a focal length of the reflective surface46A is at least as large as the aperture of the reflective surface 46A.In such a configuration, wavelength-dependent cancellation is mitigatedby making the path lengths of the reflected wavelengths closer to thesame size. A transducer 46B suitable for measurement of ultrasonicradiation 6 typically is more sensitive to on axis signals than off axissignals. As a result, making the focal length of the reflective surface46A at least as long as the aperture serves to reduce the maximum angleof the rays, improving the response.

In an illustrative embodiment, reflective surface 46A comprises aspherical shape comprising an aperture of approximately eight inches anda focal length of approximately eleven inches. Such a configuration canproduce approximately a nineteen decibel gain at a frequency of thirtykHz. In this case, acoustic sensor 18B can enable the measurement of aleak as small as five grams/sec, which corresponds to a leak generatedby eight pounds per square inch (psi) of pressure across an orifice0.097 inches in diameter at a distance of approximately seventy-fivefeet. At seventy-five feet, the beamwidth is +/− seven degrees, therebyalso providing good localization for the leak and/or flame source.Currently, a spherical shape reflective surface 46A is more readilyavailable with large focal length to aperture ratios as compared to anequivalent gain parabolic shape. However, it is understood thatembodiments of the invention can be implemented with an equivalent gainparabolic shape.

As described herein, the acoustic data acquired by sensing device 18Bcan be processed by computer system 20 (FIG. 1) to automatically detecta leak and/or flame of a pressurized fluid. To this extent, FIGS.10A-10C show illustrative acoustic frequency spectra according to anembodiment. In particular, FIG. 10A shows the frequency spectrum for atypical outdoor city environment, which can serve as a baseline forevaluation of leaks and/or flames. FIG. 10B shows the frequency spectrumtaken in the same setting as that of FIG. 10A, but with a leak of sixtypsi hydrogen gas through an orifice of 0.097 inches located at adistance of seventy-five feet. FIG. 10C shows the frequency spectrumafter the hydrogen gas leak was ignited to produce a steady flame. FIG.10C shows a prominent additional broad peak centered in the audiblespectrum at approximately two kHz. The magnitude of the sound was muchlouder in both audible and ultrasonic regions of the spectrum afterignition of the flame.

FIG. 11 shows an illustrative process for automatically identifying thepresence of a leak and/or a flame in a monitored area using acousticdata according to an embodiment, which can be implemented by environment10 (FIGS. 1 and 2). Referring to FIGS. 2 and 11, in action 202, computersystem 20 can perform one or more initialization actions. For example,computing device 16A can initialize a counter stored as part ofmonitoring data 34A, which keeps track of a number of consecutiveoccurrences of acoustic peaks present in the acoustic data, which pass asufficient number of tests for consideration as potential leaks orflames. In action 204, computing device 16B can obtain a currentacoustic sample from one or more sensing devices 18B, and store it asraw monitoring data 34B. In an embodiment, the acoustic sample isoptimized for acoustic data in the range of 10-40 kHz. However, theacoustic sample can include acoustic data for all frequencies between 10Hz-100 kHz, or greater. Computing device 16B can filter the acousticsample and store acoustic data corresponding to only those frequencyranges of value in determining whether a leak and/or flame may bepresent as monitoring data 34B. In an embodiment, a sample period cancomprise approximately 0.5 seconds. However, it is understood that anysampling rate can be selected based on the application.

In action 206, computing device 16B can calculate the fast Fouriertransform (FFT) and the FFT envelope for the acoustic sample using anysolution, which can be stored as monitoring data 34B. In action 208,computing device 16B can curve fit the FFT envelope to identify specificmaxima that are greater than one octave half power bandwidth using anysolution. Computing device 16B can store the peak value and Q factor(the ratio of the peak value to the bandwidth in octaves) as monitoringdata 34B for further processing.

In action 210, computing device 16A can compare the newly acquiredmonitoring data 34B, including the peak value and Q factor, with astored running background of unremarkable spectra stored as monitoringdata 34A. For example, the running background can comprise spectra datafor various acoustic samples acquired over a recent time frame, e.g.,ten minutes. In action 212, computing device 16A determines whether anypeaks are present in the acoustic data that are a minimum amount (e.g.,ten decibels) above the running background. If not, computing device 16Acan add the newly acquired monitoring data 34 to the running background,and processing for the sample is complete. Additionally, when utilizedcomputing device 16A can reset the counter described herein.

If one or more sufficient peaks are present in the acoustic data, inaction 214, computing device 16A can determine whether the peak(s) havebeen present for a minimum amount of time. For example, computing device16A can increment a counter and determine whether the counter exceeds athreshold number (e.g., three). If the peak(s) have not been present fora sufficient amount of time, processing for the current acoustic sampleis complete. Otherwise, in action 216, computing device 16A can comparethe peak(s) of the current acoustic sample to a library of applicationspecific backgrounds. For the example, the library can include knowntransitory nature peaks that may occur in the particular environment inwhich sensing device 18B is installed.

In action 218, computing device 16A can determine whether any peaksabove a threshold (e.g., 20 kHz) are present, which are not classifiedas background. For example, computing device 16A can compare the peakvalue and Q factor using an application-specific variance threshold. Ifone or more peaks are present, in action 220, computing device 16A candetermine whether any non-background peak is present within a flame-onlyrange of frequencies (e.g., 1-5 kHz). If so, in action 222, computingdevice 16A can determine that a flame is present. If not, in action 224,computing device 16A can determine that a leak is present. In eithercase, computing device 16A can provide data for use by one or more users12 as described herein.

While the operations on acoustic and image data have been shown anddescribed herein as being independently performed by computing devices16A, 16B, it is understood that an embodiment of the invention can usefused acoustic and image data for the detection of a flame and/or leak.For example, acoustic data can be used to supplement the detection of aflame using image data and vice versa. In this case, the lack of anyacoustic signal data indicating a flame or image data indicating a flamewhen the other sensor data indicates such a presence can be used tosuppress what could otherwise be a false alarm, or supplement dataprovided for use by a user 12 (e.g., indicating that computer system 20could not definitively determine whether a flame is present or not).

Additionally, it is understood that the particular acts and order ofacts in the respective processing described in conjunction withcomputing devices 16A, 16B are only illustrative, and variousalternatives are possible. Similarly, computing devices 16A, 16B areonly illustrative of various implementations of computer system 20,which are capable of performing processing described herein. To thisextent, it is understood that one or more of the actions described asbeing performed by computing device 16A or 16B can be performed by theother computing device 16A or 16B, an analog computing device, and/orthe like.

Furthermore, it is understood that various features described herein maynot be implemented for some implementations of environment 10. Likewise,some implementations of environment 10 can include additional features.For example, a number of sensing components 14, a configuration of eachsensing device 18A (e.g., a lens) and/or 18B (e.g., necessity of a gainelement), etc., can vary based on, for example, desired monitoring(e.g., monitoring for leaks only may not require any image sensingdevices 18A, while monitoring for a flame only, such as to ensure that adesired flame remains present, may not require any acoustic sensingdevices 18B), an indoor monitored area, an area providing limitedaccess, a range of the monitored area, obstacles present within themonitored area, and/or the like.

Moreover, an embodiment of environment 10 can include self testfunctionality, e.g., when implemented in a critical application wheresensor outputs and alarms are used for control and/or safety purposes.The self test functionality can insure faulty sensors do not result inexpensive delays or compromise safety. For example, an ultrasonic signalsource that generates a known ultrasonic signal can be placed inproximity to the acoustic sensing device 18B, e.g., in an area adjacentto a potential leak source. Similarly, a radiation source that generatesa known electromagnetic signal can be located within the field of viewof an imaging device. In either case, such a source can be activatedduring a self test and computer system 20 can compare the response ofsensing device 18B with an expected result.

Environment 10 can be implemented as a portable (e.g., handheld) device,which is battery powered. For example, the portable device can bemaneuvered by a robot and provide information to a remotely located user12. Alternatively, the various outputs of computer system 20 can beprovided to a monitor, headphones/speakers, alarm light or buzzer,and/or the like, which is integrated into the portable unit.

Sensing component 14 can be implemented as a single physical housing,which includes both an image and acoustic sensing device 18A, 18B. Thesensing component 14 can be directed to acquire image and acoustic datafrom a direction in which one or more potential leak and/or flamesources are present. When environment 10 includes multiple sensingcomponents 14, each sensing component 14 can be configured to monitorsome or all of the area from a different viewpoint. In an embodiment, asensing component 14 is mounted on a pole, and is configured to acquireimage and acoustic data from a generally downward direction.

While shown and described herein as a method and system for monitoringan area, it is understood that aspects of the invention further providevarious alternative embodiments. For example, in one embodiment, theinvention provides a computer program fixed in at least onecomputer-readable medium, which when executed, enables a computer systemto monitor an area. To this extent, the computer-readable mediumincludes program code, such as monitoring program 30 (FIG. 1), whichimplements some or all of a process described herein. It is understoodthat the term “computer-readable medium” comprises one or more of anytype of tangible medium of expression, now known or later developed,from which a copy of the program code can be perceived, reproduced, orotherwise communicated by a computing device. For example, thecomputer-readable medium can comprise: one or more portable storagearticles of manufacture; one or more memory/storage components of acomputing device; paper; and/or the like.

In another embodiment, the invention provides a method of providing acopy of program code, such as monitoring program 30 (FIG. 1), whichimplements some or all of a process described herein. In this case, acomputer system can process a copy of program code that implements someor all of a process described herein to generate and transmit, forreception at a second, distinct location, a set of data signals that hasone or more of its characteristics set and/or changed in such a manneras to encode a copy of the program code in the set of data signals.Similarly, an embodiment of the invention provides a method of acquiringa copy of program code that implements some or all of a processdescribed herein, which includes a computer system receiving the set ofdata signals described herein, and translating the set of data signalsinto a copy of the computer program fixed in at least onecomputer-readable medium. In either case, the set of data signals can betransmitted/received using any type of communications link.

In still another embodiment, the invention provides a method ofgenerating a system for monitoring an area. In this case, a computersystem, such as computer system 20 (FIG. 1 or 2), can be obtained (e.g.,created, maintained, made available, etc.) and one or more componentsfor performing a process described herein can be obtained (e.g.,created, purchased, used, modified, etc.) and deployed to the computersystem. To this extent, the deployment can comprise one or more of: (1)installing program code on a computing device; (2) adding one or morecomputing and/or I/O devices to the computer system; (3) incorporatingand/or modifying the computer system to enable it to perform a processdescribed herein; and/or the like.

Environment 10 can be implemented to perform monitoring in amission-critical location. In a specific application, environment 10 canbe utilized to monitor a spacecraft launch complex. In this case,personnel are not allowed to be present when hydrogen operations, suchas fuel loading, are occurring at the complex. Other illustrativeapplications include monitoring various facilities that store or usepressurized fluids that are prone to leakage, ignite easily, and/or burnwith invisible flames, such as rocket launch and test facilities,alcohol production and storage facilities, and/or the like.

The foregoing description of various aspects of the invention has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formdisclosed, and obviously, many modifications and variations arepossible. Such modifications and variations that may be apparent to anindividual in the art are included within the scope of the invention asdefined by the accompanying claims.

1. A system comprising: at least one sensing component, the at least onesensing component including: an imaging device, wherein the imagingdevice is configured to acquire image data for an area based onelectromagnetic radiation having wavelengths only corresponding to atleast one region of the electromagnetic spectrum in whichelectromagnetic radiation from an ambient light source is less than theelectromagnetic radiation emitted by at least one type of flame; and anacoustic device, wherein the acoustic device is configured to acquireacoustic data for the area; a computer system including at least onecomputing device, wherein the computer system is configured to monitorthe area by performing a method comprising: evaluating the image datafor a presence of a flame of the at least one type of flame; evaluatingthe acoustic data for a presence of at least one of: the flame or a leakof a pressurized fluid; and providing monitoring data for use by a userbased on the evaluated presence of at least one of: the flame or theleak.
 2. The system of claim 1, wherein the ambient light sourcecomprises the sun, and wherein the at least one region includes at leastone infrared region in which most sunlight is absorbed by theatmosphere.
 3. The system of claim 1, wherein the imaging devicecomprises: a camera sensitive to electromagnetic radiation havingwavelengths up to approximately 1250 nanometers; and a low pass filterconfigured to filter electromagnetic radiation passing to the camera,wherein the low pass filter comprises a cut on wavelength ofapproximately 1150 nanometers.
 4. The system of claim 1, wherein thetype of flame comprises a hydrogen flame, and the at least one regioncomprises at least a portion of an infrared region between approximately800 nanometers and approximately 1250 nanometers.
 5. The system of claim1, wherein the acoustic device comprises: a reflective surface, whereinthe reflective surface is at least one of: a parabolic or a sphericalshape; and a transducer configured to convert acoustic signals acquiredat a focal point of the reflective surface into acoustic data.
 6. Thesystem of claim 5, wherein the acoustic device is configured to enhanceacoustic signals in a range of frequencies corresponding to the leak. 7.The system of claim 6, wherein a focal length of the reflective surfaceis at least as large as an aperture of the reflective surface.
 8. Thesystem of claim 1, wherein the evaluating the image data includes:identifying a set of objects within the image data; applying a set offlame detection rules to each object in the set of objects; identifyingan object as a candidate flame in response to a minimum number of theset of flame detection rules indicating that the object is a flame; andevaluating a candidate flame as a flame in response to the minimumnumber of the set of flame detection rules indicating that the candidateflame is a flame for a minimum amount of time.
 9. The system of claim 1,wherein the evaluating the acoustic data includes: determining whetherthe acoustic data includes any non-background peaks within a firstrange, wherein inclusion of at least one non-background peak within thefirst range indicates a presence of at least one of: a leak or a flame;and determining whether the acoustic data includes any non-backgroundpeaks within a second range in response to determining the inclusion ofat least one non-background peak within the first range, wherein theinclusion of at least one non-background peak within the second rangeindicates the presence of a flame and no at least one non-backgroundpeak within the second range indicates the presence of a leak.
 10. Asystem comprising: at least one sensing component, the at least onesensing component including: an imaging device, wherein the imagingdevice is configured to acquire image data for an area; and an acousticdevice, wherein the acoustic device is configured to acquire acousticdata for the area and enhance acoustic signals in a range of frequenciescorresponding to a leak of a pressurized fluid present in the area, theacoustic device including: a reflective surface, wherein the reflectivesurface is at least one of: a parabolic or a spherical shape having afocal length that is at least as large as an aperture of the reflectivesurface; and a transducer configured to convert acoustic signalsacquired at a focal point of the reflective surface into acoustic data;a computer system including at least one computing device, wherein thecomputer system is configured to monitor the area by performing a methodcomprising: evaluating the image data for a presence of a flame of theat least one type of flame; evaluating the acoustic data for a presenceof at least one of: the flame or a leak of the pressurized fluid; andproviding monitoring data for use by a user based on the evaluatedpresence of at least one of: the flame or the leak.
 11. The system ofclaim 10, wherein a cross section of each of: the transducer and asupport structure for the transducer is less than one half a wavelengthof acoustic signals in the range of frequencies corresponding to theleak.
 12. The system of claim 10, wherein the evaluating the acousticdata includes: determining whether the acoustic data includes anynon-background peaks within a first range, wherein inclusion of at leastone non-background peak within the first range indicates a presence ofat least one of: a leak or a flame; and determining whether the acousticdata includes any non-background peaks within a second range in responseto determining the inclusion of at least one non-background peak withinthe first range, wherein the inclusion of at least one non-backgroundpeak within the second range indicates the presence of a flame and no atleast one non-background peak within the second range indicates thepresence of a leak.
 13. The system of claim 10, wherein the imagingdevice is configured to acquire image data for the area based onelectromagnetic radiation having wavelengths only corresponding to atleast one region of the electromagnetic spectrum in whichelectromagnetic radiation from an ambient light source is less than theelectromagnetic radiation emitted by at least one type of flame
 14. Thesystem of claim 13, wherein the imaging device comprises: a camerasensitive to electromagnetic radiation having wavelengths up toapproximately 1250 nanometers; and a low pass filter configured tofilter electromagnetic radiation passing to the camera, wherein the lowpass filter comprises a cut on wavelength of approximately 1150nanometers.
 15. The system of claim 10, wherein the evaluating the imagedata includes: identifying a set of objects within the image data;applying a set of flame detection rules to each object in the set ofobjects; identifying an object as a candidate flame in response to aminimum number of the set of flame detection rules indicating that theobject is a flame; and evaluating a candidate flame as a flame inresponse to the minimum number of the set of flame detection rulesindicating that the candidate flame is a flame for a minimum amount oftime.
 16. A system comprising: an imaging device, wherein the imagingdevice is configured to acquire image data for an area based onelectromagnetic radiation having wavelengths only corresponding to atleast one region of the electromagnetic spectrum in whichelectromagnetic radiation from an ambient light source is less than theelectromagnetic radiation emitted by at least one type of flame; and acomputer system including at least one computing device, wherein thecomputer system is configured to monitor the area by performing a methodcomprising: evaluating the image data for a presence of a flame of theat least one type of flame; and providing monitoring data for use by auser based on the evaluated presence of the flame, wherein themonitoring data includes annotated image data of the area.
 17. Thesystem of claim 16, further comprising an acoustic device, wherein theacoustic device is configured to acquire acoustic data for the area andenhance acoustic signals in a range of frequencies corresponding to aleak of a pressurized fluid present in the area, wherein the methodfurther comprises evaluating the acoustic data for a presence of atleast one of: the flame or a leak of the pressurized fluid, and whereinthe providing is further based on the acoustic data evaluating.
 18. Thesystem of claim 17, the acoustic device including: a reflective surface,wherein the reflective surface is at least one of: a parabolic or aspherical shape having a focal length that is at least as large as anaperture of the reflective surface; and a transducer configured toconvert acoustic signals acquired at a focal point of the reflectivesurface into acoustic data;
 19. The system of claim 17, wherein theacoustic device and the imaging device are each configured to acquirethe data from a generally downward direction.